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Tsunamis

Tsunamis are a series of large waves that strike coastal areas. They can happen with little warning and result in flooding and damage to coastal communities. Thankfully, they are a rare event. Storm surges are more common. Residents, particularly those living in low-lying areas near the coastline, should prepare in advance.

What to do:

Tsunami facts

Tsunamis are a series of large waves caused by events such as submarine earthquakes, landslides, volcanic eruptions, and less commonly, meteoric impacts. Tsunamis can also occur in large lakes.

They can occur with little warning in the ocean and in lakes.

A tsunami can be triggered by a large, high energy, but relatively short duration disturbance of the sea floor. Such waves can travel across the ocean at high speed (800 km/h, the speed of a jet plane).

As the tsunami waves approach the shoreline and water depth shallows, the wave speed slows, but wave height will increase as wave length decreases. In 20 m of water, wave speed will be 50 km/h.

Tsunamis can occur as individual or multiple waves following each other by minutes and even hours.

Tsunamis can grow to 60 or more metres in height (the size of a ten-story building).